docs: def ngrams(path, elem, ignore_hash=True):
      """
      Yields N-grams from a JSTOR DfR dataset.
  
      Parameters
      ----------
      path : string
          Path to unzipped JSTOR DfR folder containing N-grams.
      elem : string
          Name of subdirectory containing N-grams. (e.g. 'bigrams').
      ignore_hash : bool
          If True, will exclude all N-grams that contain the hash '#' character.
  
      Returns
      -------
      ngrams : :class:`.FeatureSet`
  
      """
  
      grams = GramGenerator(path, elem, ignore_hash=ignore_hash)
      return FeatureSet({k: Feature(f) for k, f in grams})